<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>CssSettingButtonColor</title>
    <style>
        .button1
        {
            background-color: #b81d30;
        }
        .button2
        {
            background-color: #1a29b8;
        }
        .button3
        {
            background-color: #888888;
        }
        .button4
        {
            background-color: black;
        }
        .button5
        {
            background-color: #4aff59;
        }
        button
        {
            /*设置大小*/
            font-size: 20px;
            /*边界*/
            border: none;
            color: #f9f0ff;
            padding: 15px 30px;
            text-align: center;
            /*文字装饰*/
            text-decoration: none;
            /*显示：内联*/
            display: inline-block;
            margin: 4px 2px;
            /*光标*/
            cursor: pointer;
            /*圆角矩形*/
            border-radius: 12px;
        }
    </style>
</head>
<body>
<button class="button button1">Red</button>
<button class="button button2">Blue</button>
<button class="button button3">Gray</button>
<button class="button button4">Black</button>
<button class="button button5">Green</button>
</body>
</html>